Many medical articles used in hospitals and clinics are designed for one-time use. Articles which have sharp points, cutting edges and the like, are collectively known as sharps, and many disclosures of special equipment and procedures have been proposed to minimize the danger of injury such as needle sticks, to personnel involved in the use or disposal of these articles. Safe handling and disposal is particularly important, since a sharp is often used in a procedure, such as blood sampling, and as a result may be contaminated with a potentially infectious agent.
Many designs of disposal equipment for sharps have been proposed. Most include a storage container having a lid with locking closure features and several openings through the lid for access to the interior of the container. Often the sharp is affixed to a hub having threads mated to a tube holder, and it is conventional that one of the openings have structure associated therewith, known as the unwinder, for unthreading the sharp from the holder without any manual manipulation by the user.
Conventional unwinders operate by inserting a needle-hub member into the large end of a V-shaped opening and advancing the member toward the narrow end of the opening until ribs on the hub engage the wall of the unwinder. At this point, a twisting rotation of the needle holder causes the hub-needle member to drop off into the container. A common problem encountered with this design is hangup of the hub on the wall after removal of the holder, and occurs when the hub has engaged the wall too strongly. Typical sharps containers having an unwinder designed to unthread needle-hub members are disclosed in U.S. Pat. No. 4,375,849 to Hanifl and U.S. Pat. No. 5,415,315 to Ramiriz et al. respectively. An unwinder for double-ended needles is disclosed in U.S. Pat. No. 5,092,462 to Sagstetter et al.
While the above disclosures have advanced the art of sharps disposal, prior art unwinders do not perform well for disposal of sharps protected by a modern safety shield which prevents the unwinder from grasping the ribs. Thus, if a needle-hub-shield unit is advanced in a conventional unwinder, the shield must be tightly wedged between the opposite walls of the unwinder, often leading to severe hangup. Further, many reports from field use have described inadvertent premature raising-up of the holder by the technician before complete disengagement of the hub threads from the holder threads, a common occurrence also causing holdup and failure of the sharp to drop into the container. The present invention is directed to an unwinder design directed to overcoming these problems.